Q. The magnetized wire of moment M and length l is bent in the form of semicircle of radius r. Then its magnetic moment is
A) $\frac{2M}{\pi}$
B) 2 M
C) $\frac{M}{\pi}$
D) Zero
Explanation
(a) On bending a wire its pole strength remains unchanged whereas its magnetic moment changes
[image:5_image40.emf]
New magnetic moment,
$M^{''} = m(2r) = m\left( \frac{2l}{\pi} \right) = \frac{2M}{\pi}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.